Pulsed IV characterization of GaN HEMTs for high frequency, high efficiency integrated power converters

Commercial foundry 0.25μm RF GaN MMICs were characterized as power switches using pulsed IV system. The devices exhibited current collapse and ON resistance modulation. These trap effects were highly dependent on off state quiescent drain bias voltages. At higher switch voltages, the output power was reduced due increase in the ON resistance and collapse of drain current. Traps located on the surface between gate and drain caused degradation in the ON resistance while the traps in the bulk beneath the gate plate altered the pinch-off voltage. A power HEMT model incorporating traps was developed and simulations correctly predicted knee walk out due to increase in the ON resistance and current collapse associated with change in pinch-off volatage due to bulk traps.